1. Technical Field
The present invention relates to a decorated sheet integrated at the time of molding with a printing material that has previously been printed on the surface of a synthetic resin, an ink used for manufacturing the decorated sheet, and an injection molded article integrated with the decorated sheet.
2. Related Art
Among processes to apply decorations onto the surface of a synthetic resin molded article, there is known a synthetic resin molding process (hereinafter often referred to as a film insert molding process) in which a printing material such as a synthetic resin sheet or film that has previously been printed by ink (hereinafter often referred to as a decorated sheet) is loaded in a mold, and a synthetic resin is injected into the mold for integration with the decorated sheet.
This process has one feature of being capable of applying decorations even on molded article that encounters difficulty in application of direct coloration, patterning, etc. by printing on a surface of the molded article. Another advantage is that since a printed layer formed on the decorated sheet can be held in close contact between the synthetic resin molded article and a substrate sheet or film of the decorated sheet, much better scratch resistance is achievable as compared with printing processes for the surfaces of molded articles, and the resulting decorated article is less likely to change with time. Thus, this process is used for application of decorations onto the surfaces of various equipments inclusive of not only small electronic equipment such as cellular phones and PCs, but also various electric appliances and automobile parts.
Conventionally, in the film insert molding process, various proposals have been submitted to improve mutual adhesiveness among a sheet forming a decorated layer, a colored layer forming ink and a synthetic resin filled for molding when forming colored layers by printing.
In JP-A-2003-285404, for example, it is proposed to improve adhesiveness with a polypropylene resin by providing two or more anchor layers and an adhesive layer of a specified composition after having formed colored layers on a thermoplastic resin sheet by printing.
However, by the film insert molding process, there are formed various molded article products such as those having corrugated surfaces and discontinuous decorated layers.
For such molded articles, it is sometimes insufficient that only the adhesiveness between the substrate of a decorated sheet and colored layers or adhesiveness between the colored layers and a molding resin is taken into consideration. For a decorated film that has refined design by both of the color of the molding resin and the decorated layer, for example, there is sometimes a problem that there exist many areas where no colored layer is formed and that in such areas, adhesiveness between the decorated film and the molding resin becomes insufficient, thereby separating the decorated film from the resin depending on its shape.
It is an object of the present invention to provide a decorated sheet having a high adhesive strength between the decorated sheet and a molding resin regardless of the shapes of printing images formed on the decorated sheet and the shapes of molded articles, causing no peeling and having a good weather resistance and to provide molded articles using the decorated sheet.